At what depth does gas narcosis typically occur in divers?

Gas narcosis, often referred to as "the martini effect," is a phenomenon that affects divers due to the increased partial pressure of nitrogen in their breathing gas at greater depths. The depth at which gas narcosis typically begins to noticeably affect divers is generally recognized to be around 30 to 40 meters (100 to 130 feet).

At these depths, the environmental pressure increases significantly, resulting in a higher concentration of nitrogen in the bloodstream. This can lead to cognitive impairments and a range of impaired physical and mental functions, similar to the effects of alcohol intoxication. Divers may experience a false sense of euphoria, impaired judgment, and decreased motor coordination, which can be dangerous if not recognized.

It's important for divers to be aware of this effect and to practice depth management, maintaining clear communication with buddies and adhering to dive planning and safety protocols to mitigate the risks associated with narcosis. Understanding the onset depth of gas narcosis is essential for safe diving practices, particularly for those who may be diving deeper than recreational limits.